1. Field of the Invention
The present invention relates to an aligning method and apparatus used in letterpress printing and more particularly to a method and apparatus for attaching a printing plate to a plate holder.
2. Prior Art
Conventionally, printing plates are attached to plate holders as follows: a printing plate is first removed from a plate holder attachment while a two-sided tape is put on the attachment surface of a plate holder. Then, the printing plate is next clamped by pincette and placed on the attachment surface of the plate holder in a manner that the printing plate matches the standard line of the attachment surface. Thereafter, the upper surface of the printing plate is pressed with a flat item so that the printing plate is adhered to the two-sided tape.
Since the above described conventional technique is performed manually, the printing plate is not always accurately attached to the plate holder. Thus, skillfulness is required. In addition, after the printing plate is attached, printing is performed. Positional discrepancy is then checked, whether or not any has occurred. If a positional discrepancy is found, the printing plate is removed and then attached again manually with a visual estimate. Removing and re-attaching are repeated until positional discrepancy is eliminated. Accordingly, a considerable amount of time is required for corrections, and since the printing plate is attached manually, the printing plate can easily change its shape.